1) Field
The general inventive concept relates to a surface acoustic wave (“SAW”) sensor and, more particularly, to a device including the SAW sensor and a method of controlling a liquid using the same.
2) Description of the Related Art
A surface acoustic wave sensor is a device that senses, e.g., detects, a target material, such as an analyte, using a surface acoustic wave (“SAW”).
Generally, the SAW sensor is disposed on a substrate made of a piezoelectric material, and includes a receptor that binds to a specific desired target material on a surface of the SAW sensor. More specifically, when a solution containing the target material flows into the SAW sensor, signals, such as wavelengths, for example, are changed by mechanical, chemical and/or electrical reactions of the target material with the receptor. As a result, properties and/or characteristics of the target material may be determined by monitoring the changes in the signals.
A SAW sensor device is typically used to analyze and monitor a target material contained in a sample, such as a chemical liquid sample or a biological liquid sample (such as a body fluid, for example).
The SAW sensor is particularly sensitive to a pressure of a liquid, as well as to viscosity or density of a medium (such as the liquid), and corresponding mass changes on a surface of the SAW sensor. Accordingly, precise control of the liquid is desired to minimize noise, which is a signal change due to factors other than the detected mass changes, for example.
There is typically an abundant amount of target materials in a given target sample solution analyzed by the SAW sensor, and the abundant target materials cause contamination of valves and pumps, as well as channels and chambers, for example, in the SAW sensor device, as the liquid flows through the SAW sensor. As a result of the contamination, substantial errors are introduced when the target sample solution is analyzed.
To reduce and/or effectively prevent these and other errors, disposable, i.e., not reusable, valves and pumps are used. However, using disposable valves and pumps has disadvantages, which include reducing commercial and economic feasibility and efficiency of the SAW sensor.